QGIS: Map theme with layer visibility AND style, does it exist?

Question

I'm using QGIS to do urban visualisation on large scale territory, I'm used to working with Archicad which has an amazing option called "Graphic Overrides", it's a way to create different layer style (for multiples layers) and quickly switch between them. It's really great to create different visualisation.

I'm now working with QGIS as I'm working with more data, and I haven't find a good workflow to quickly change styles on multiples layers. I'm talking about unique style per layer saved as a "combination", so I can quickly switch between different visualisation.

Map theme is almost that, but it only switch layer visibility. I know I can save layer style independently and apply theme, but when you want to switch multiple layers, the workflow becomes really cumbersome.

What I wish:

• have a list with different combination, which saved styles per layer.
• being able to switch between them easily, like the map theme.

What is the closest thing to that in QGIS 3.1x ?

Answer 1

You can do this using named styles and themes.

For any layer, right click, choose Styles / Add to create a new named style. Style changes you make from then on are part of that named style. When you right click, choose Styles and select another style from the list (e.g. default), the previous setting are retained for that named style but you switch to the one you've just selected.

A theme (see the Manage map themes icon in the Layer panel) is a combination of layers to be shown and the named style to be used for each. If you're not using named styles, it will be the default style for each, but if at the time you save the theme, you have a different style active for a specific layer, that's what will be saved as part of the theme.

I use this extensively. I have a Map theme, which uses the default style for each constituent layer suitable for a (topo) map. I have an Aerial theme, which uses aerial photo imagery rather than contours, etc., as the basemap, and also switches trails and placemarks to different styles, named Aerial, that contrast better with it. See example below, with a clip of the right-click style menu overlaid.

What's great is I can tweak e.g. a layer's Aerial style while in the Aerial theme, then switch to the Map theme (and map style) with a click, and still preserve my Aerial tweaks for the next time I choose that theme, since I am now using default style for each visible layer (all changes saved when I save the project.)